Poorly crystalline hydroxyapatite was improved so that it has better cell affinity in vitro. We studied the efficacy of a novel resorbable poorly crystalline hydroxyapatite-based biphasic calcium phosphate, BonaGraft, for bone regeneration in vivo. The beagle was used as an animal model, and cylindrical artificial bone defects (3 mm in diameter and 6 mm long) were produced in the alveolar bone. The BonaGraft (ratio of poorly crystalline hydroxyapatite to b-tricalcium phosphate, 60:40) was used to fill in the defect, and unfilled defects served as a control group. At 5, 8 and 10 weeks after the operation, the size of the residual graft and new bone formation were evaluation by a histomorphometric analysis. In a clinical trial, 33 enrolled patients included 15 males and 18 females with ages ranging from 35 to 54 years. The main indications were ridge augmentation (n = 12), sinus lifting (n = 2), repair of periodontal disease (n= 14), and repair of radicular cysts (n= 5). The clinical outcomes of the surgery were primarily evaluated by clinical radiographs. In the animal study, implanting BonaGraft produced greater new-bone formation (74.5 ± 1.0) at 10 weeks postoperatively than that of the control (40.2 ± 0.3). BonaGraft particles were gradually resorbed and substituted by bone. The in vivo graft resorption time and bone healing time of 12.1 weeks were mathematically determined by the least squares method. In the clinical test, all patients implanted with BonaGraft reported satisfactory clinical outcomes without major material-related side effects. According to the radiographic pictures, implantation of BonaGraft enhanced bone formation. According to the animal study results, BonaGraft has a suitable resorption period and satisfactory outcomes of new bone formation. The clinical study produced high satisfaction with clinical results both objectively and subjectively. For this reason, BonaGraft seems to be an alternative choice for a bone substitute in dental applications. © 2010 Association for Dental Sciences of The Republic of China.